In this project, Neuropsychological data will be obtained at baseline from controls and non-demented subjects with cognitive impairments who will be recruited through the Clinical Core and followed over time. The overall goal of the Neuropsychological project is to determine whether neuropsychological data can be used to predict which non-demented individuals with cognitive problems will develop progressive cognitive data, which will progress to the pint where they meet criteria for AD, and which will remain stable. By adding two neuropsychological tests to the annual review in which the subjects participate, we also propose to determine whether such testing can serve as a surrogate for a detailed clinical interview by a skilled clinician. In addition, we will seek to determine the relationship between neuropsychological measures and other information obtained on the same individuals by the cores and the projects, including clinical data, genotype status, volumeric MRI, cerebral perfusion, and fMRI signal change. An implicit assumption underlying the goals of the project is that, by examining the performance of non-demented individuals with a range of cognitive difficulty, and relating performance to a variety of measures that reflect the in vivo status of the brain, as well as other relevant clinical and genetic data, it will be possible to determine the evolution of brain changes that occur during prodromal AD, and the neuropsychological measures that are best suited to identifying these changes.